States where medical marijuana is legal saw a decrease in Medicare Part D spending (that’s the part that covers prescription drugs). A study published Wednesday found that prescriptions for painkillers and antidepressants fell in states where medical marijuana could be obtained as an alternative. But, prescriptions for other drugs, like blood thinners, stayed stable. Conclusion? Buy stock in whoever owns Doritos. Another conclusion? Medical marijuana seems to have saved Medicare $165.2 million in 2013. While that’s less than half a percent of Medicare spending, it suggests that people are using marijuana for medical purposes. Your cousin in Colorado totally called it.